(1) Field of the Invention
The present invention relates to high strength, porcelains which can favorably be used for insulators necessitating high strength and to a process for producing the same.
(2) Related Art Statement
There have formerly been demands to increase the strength of insulators, and thus development of high strength porcelains has been expected.
In order to obtain high strength porcelains, it is known that an amount of alumina in porcelains is increased or the grain size of bodies is made finer.
However, among the above conventional techniques for producing high strength porcelains, increasing the amount of alumina in porcelains must inevitably use a great amount of expensive alumina, which raises production cost of insulators. Further, although strength is increased, formability is deteriorated.
On the other hand, in the technique to make the grain size of bodies finer, the bodies are likely to crack due to shrinkage during forming, drying or firing of insulators.